CD sound quality: original pressings vs regular remaster vs MFSL, etc

+1 @georgehifi . I do the same thing. 
And like @falconquest  i Google Steve Hoffman to find a recommendation.

Agree with @duckworp. After hearing some terribly compressed rock CDs on my home system, I set out to find the best quality releases of my favorite rock bands.
I listen mainly to classical and the quality of Redbook sounds so good thru my system, I couldn't listen to the vastly inferior rock albums.

Using the Steve Hoffman Forum and Discogs I researched early releases of Zeppelin, Hendrix, Pink Floyd, Heart (known to be excellent recordings), and others. The first generation of CDs issued 1984 thru 1987 were the best by far. Now that digital playback technology has caught up to the silver discs, these albums sound very analogue-like.
CDs pressed in '84 and '85 mostly came from Germany and UK since the US pressing plants weren't up to speed yet. 

The Zeppelin CDs from Germany consistently had  higher quality sonics than the same albums pressed in the US and UK. These were early and 1st releases. Some Japanese releases were excellent as well, but were usually more detailed and not as musical. 
I grew up in the analogue days (vinyl and tape) so tape hiss is to be expected on recordings. In fact, it's a good sign that the music isn't overly compressed.

OTOH, there are many recordings from the 60s, 70s, and 80s that are of poor sound quality. These are the CDs that remastering was able to improve. Except for remastering performed during the Loudness Wars.

As @stilljim stated, some of the early US CDs were incorrectly mastered using the RIAA equalization for vinyl records. These CDs were pressed and sold by retailers. I believe these discs were recalled, but in any event, this hurt the public's experience with the new format.
These albums were then mastered and released using the proper EQ for the digital standard. 

The Blue-spec was Wayy open sounding...like way more than most. The vocals sounded ok, but not like the original vinyl back in the day. A sort of nice, if over-hyped, uber-detailed kind of sound overall.

Blu-spec and other Japanese remasters usually have very good dynamics, but an analytical presentation. With some of these remasters it seems like they are trying to achieve the best specs and with so much detail makes them less musical. I have quite a few Blu-specs that I don’t play anymore. Many standard Japanese pressings sound better to me.

IME, the best Japanese remaster technology is XRCD. It is a product of JVC and involves using a 20 bit sampling rate plus using a glass master in which a laser cuts the pits more precisely than standard CD technology. This provides better jitter control.
I only own 2 XRCD’s due to the high cost, but they sound far superior to other CD remasters. I still prefer finding an early release from the first production run.